Adding tests for all PennyLane transforms (#1215)

This PR adds unit tests for all PennyLane transforms. This PR addresses
[sc-72626].

---------

Co-authored-by: Ali Asadi <10773383+maliasadi@users.noreply.github.com>
Co-authored-by: David Ittah <dime10@users.noreply.github.com>
Co-authored-by: erick-xanadu <110487834+erick-xanadu@users.noreply.github.com>
Co-authored-by: soranjh <40344468+soranjh@users.noreply.github.com>
Co-authored-by: Utkarsh <utkarshazad98@gmail.com>